Antiprotozoal Drugs

Antiprotozoals are agents used to treat protozoan infections. Protozoan infections are common in tropical areas.

Protozoans are single-celled organisms that pass through several stages in their life cycles, including at least one phase as a human parasite. While protozoans thrive in tropical climate, they may also survive and reproduce in any area where people live in very crowded and unsanitary conditions.

Disease Spotlight: Protozoal Diseases

Malaria

It is a disease characterized by a cycle of fever and chills transmitted through a bite of a female Anopheles mosquito. Identified causes include Plasmodium falciparum, vivax, malariae, and ovale. Malaria is endemic in many parts of the world.

Sporozoites travel through bloodstream and become lodged in the liver and other tissues.

Amebiasis

It is an intestinal infection caused by Entamoeba histolytica. It is often known as amoebic dysentery. The disease is transmitted through fecal-oral route.

Amebiasis is characterized by mild to fulminant diarrhea. In worst cases, it is able to invade extraintestinal tissue.

Leishmaniasis

Is a disease caused by a protozoan that is passed from sand flies to humans. It is characterized by serious lesions in the skin, viscera, and mucous membranes of host.

Trypanosomiasis

Is caused by Trypanosoma leading to African sleeping sickness and Chagas’ disease.

African sleeping sickness is caused by T.brucei gambiense and is transmitted by tsetse fly. It is characterized by lethargy, prolonged sleep, and even death.

Chagas’ disease is caused by T.cruzi and is passed to humans by common housefly. It is characterized by severe cardiomyopathy.

Trichomoniasis

Is caused by T.vaginalis, a common cause of vaginitis (reddened, inflamed vaginal mucosa, itching, burning, and yellowish-green discharge).

It is usually transmitted through sexual intercourse.

Asymptomatic in men

Giardiasis

Is caused by G.lamblia, the most commonly diagnosed intestinal parasite in the United States.

Antimalarials

Description

Antimalarials are agents used to attack Plasmodium at various stages of its life cycle. Through this, it becomes possible to prevent acute malarial reaction in individuals who have been infected by the parasite.

These agents can be schizonticidal (acting against the red-blood-cell phase of the life cycle), gametocytocidal (acting against the gametocytes), sporontocidal (acting against the parasites that are developing in the mosquito), or work against tissue schizonts as prophylactic or antirelapse agent.

Quinine (Qualaquine) was the first drug found to be effective in the treatment of malaria.

Therapeutic Action

The desired and beneficial action of antimalarials is:

Entering human red blood cells and changing the metabolic pathways necessary for the reproduction. Chloroquine, the mainstay of treatment, in addition to this main mechanism, is directly toxic to parasites and decreases the ability of the parasite to synthesize DNA.

Indications

Antimalarials are indicated for the following medical conditions:

Treatment of malaria, prevention of relapse, and other protozoal diseases like extraintestinal amoebiasis (chloroquine) and toxoplasmosis (pyrimethamine).

Here are some important aspects to remember for indication antiprotozoals in different age groups:

Children

This age group is very sensitive to the effects of most antiprotozoals and therefore more severe reactions can be expected.

In addition, many antivirals do not have proven safety and efficacy in children.

Adults

This age group should be well advised about the need for prophylaxis against various protozoal infections and the need for immediate treatment if disease is contracted.

Administration of drug in pregnant and nursing women is only justified if benefits clearly outweigh the risk.

Women of childbearing age are advised to use barrier contraceptives when any antiprotozoal drug is being taken.

Older adults

Older patients are more susceptible to adverse effects of antiprotozoal therapy, particularly those with hepatic and renal dysfunctions.

Pharmacokinetics

Here are the characteristic interactions of antimalarials and the body in terms of absorption, distribution, metabolism, and excretion:

Administer the complete course of the drug to get the full beneficial effects.

Monitor hepatic function and perform ophthalmological examination before and periodically during treatment to ensure early detection and prompt intervention with cessation of drug if signs of failure or deteriorating vision occur.

Provide comfort and safety measures if CNS effects occur (e.g. side rails and assistance with ambulation if dizziness and weakness are present) to prevent patient injury. Provide oral hygiene and ready access to bathroom facilities as needed to cope with GI effects.

Educate client on drug therapy to promote understanding and compliance.

Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

Monitor patient response to therapy (resolution or prevention of malaria).

Administer the complete course of the drug to get the full beneficial effects.

Monitor hepatic function before and periodically during treatment to ensure early detection and prompt intervention with cessation of drug if signs of failure occur.

Provide comfort and safety measures if CNS effects occur (e.g. side rails and assistance with ambulation if dizziness and weakness are present) to prevent patient injury. Provide oral hygiene and ready access to bathroom facilities as needed to cope with GI effects.

Educate client on drug therapy to promote understanding and compliance.

Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

Monitor patient response to therapy (resolution of infection and negative cultures for parasite).

Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.

Monitor patient compliance to drug therapy.

Practice Test: Antiprotozoal Agents

Practice quiz for this nursing pharmacology study guide:

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Practice Test: Antiprotozoal Agents

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Congratulations - you have completed Practice Test: Antiprotozoal Agents.
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Your answers are highlighted below.

Question 1

Chagas’ disease is passed to humans by which of the following vector?

A

female Anopheles mosquito

B

housefly

C

tsetse fly

D

dragonfly

Question 1 Explanation:

Option A is for malaria while option C is for African sleeping sickness.

Question 2

Which of the following patient statements should alert the nurse for possible high levels of quinine?

A

“I feel weak, especially after ambulating.”

B

“My throat is sore. I think I’m down with a flu.”

C

“When I went out of my bed, it felt like the room swayed.”

D

“I don’t feel like eating anything. I just want to sleep.”

Question 2 Explanation:

This might be vertigo which is part of the constellation of manifestations of cinchonism which is associated with high levels of quinine or primaquine.

Question 3

A traveler diagnosed with malaria is also receiving sulfonamide for a respiratory infection. What should the nurse watch out for in this drug combination?

A

increased intracranial pressure

B

urinary retention

C

blood component levels

D

serum BUN and creatinine

Question 3 Explanation:

This combination can lead to bone marrow suppression.

Question 4

How many days should the patient avoid alcohol after treatment with metronidazole?

A

1 day

B

3 days

C

5 days

D

7 days

Question 5

Disulfiram and tinidazole therapy can lead to increased psychotic reactions. How long after tinidazole therapy can we safely start disulfiram therapy?

A

7-10 days

B

14 days

C

3 days

D

One month

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Practice Test: Antiprotozoal Agents

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Congratulations - you have completed Practice Test: Antiprotozoal Agents.
You scored %%SCORE%% out of %%TOTAL%%.
Your performance has been rated as %%RATING%%

Your answers are highlighted below.

Question 1

Chagas’ disease is passed to humans by which of the following vector?

A

female Anopheles mosquito

B

housefly

C

tsetse fly

D

dragonfly

Question 1 Explanation:

Option A is for malaria while option C is for African sleeping sickness.

Question 2

Which of the following patient statements should alert the nurse for possible high levels of quinine?

A

“I feel weak, especially after ambulating.”

B

“My throat is sore. I think I’m down with a flu.”

C

“When I went out of my bed, it felt like the room swayed.”

D

“I don’t feel like eating anything. I just want to sleep.”

Question 2 Explanation:

This might be vertigo which is part of the constellation of manifestations of cinchonism which is associated with high levels of quinine or primaquine.

Question 3

A traveler diagnosed with malaria is also receiving sulfonamide for a respiratory infection. What should the nurse watch out for in this drug combination?

A

increased intracranial pressure

B

urinary retention

C

blood component levels

D

serum BUN and creatinine

Question 3 Explanation:

This combination can lead to bone marrow suppression.

Question 4

How many days should the patient avoid alcohol after treatment with metronidazole?

A

1 day

B

3 days

C

5 days

D

7 days

Question 5

Disulfiram and tinidazole therapy can lead to increased psychotic reactions. How long after tinidazole therapy can we safely start disulfiram therapy?

A

7-10 days

B

14 days

C

3 days

D

One month

Once you are finished, click the button below. Any items you have not completed will be marked incorrect.
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question

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1. Chagas’ disease is passed to humans by which of the following vector?

A. female Anopheles mosquito
B. housefly
C. tsetse fly
D. dragonfly

1. Answer: B. housefly.

Option A is for malaria while option C is for African sleeping sickness.

2. Which of the following patient statements should alert the nurse for possible high levels of quinine?

A. “I feel weak, especially after ambulating.”
B. “My throat is sore. I think I’m down with a flu.”
C. “When I went out of my bed, it felt like the room swayed.”
D. “I don’t feel like eating anything. I just want to sleep.”

2. Answer: C. “When I went out of my bed, it felt like the room swayed.”

This might be vertigo which is part of the constellation of manifestations of cinchonism which is associated with high levels of quinine or primaquine.

3. A traveler diagnosed with malaria is also receiving sulfonamide for a respiratory infection. What should the nurse watch out for in this drug combination?

Iris Dawn is a nurse writer in her 20s who is on the constant lookout for latest stories about Science. Her interests include Research and Medical-Surgical Nursing. She is currently furthering her studies and is seriously considering being a student as her profession. Life is spoiling her with spaghetti, acoustic playlists, libraries, and the beach.